Cement steel plate.



HA ROLD ASHTON RICHARDSON, OF LONDON, ENGLAND.

CEMENT s'rEEL PLATE.

No Drawing.

Specification of Letters Patent.

Patented Feb. 20. 1912.

Application filed October 15, 1910. Serial No. 587,342.-

To all whom it may concern: I

Be it known that I, HARoLo ASHTON RICHARDSON, a subject of the KingofGreat Britain and Ireland, and. residing at'Hyde Park Hotel,Knightsbridge, London, S. England, have invented certain new and useful'Cement Steel Plates, of which the following is a specification.

This invention relates to improved cement steel or like plates orarticles having a glass hard surface designed for armor plates, andother purposes for which plates hardened on one surface, are required.In known processes for themanufactureof such plates, a mild steelcontaining 0.3 per cent. of carbon is subjected to a cementat-ionprocess, the plates being placed in a furnace and covered with carbon onone side, and then heated for seven or'eig-ht days at a redheat. Theplates are then quenched in water, which hardens the portion of the'steel which has been carburized'. '--'In some cases the steel beforehardening has been heated to a red heat and plunged in water, and thenagain heated to a somewhat lower heat, and again plunged in water togive the plate a fibrous structure, the fibrous plate being thenhardened by subjecting the surface which requires hardening to a highertemperature, and quenching.

The object of the presentinvention is to provide an improved steel plateor like article having a hardened surface, and the invention includes aplate having the novel composition hereinafter described andparticularly defined by the" appended claims.

In carrying the invention into effect ac- Q cording to one modificationI prepare an alloy containing tungsten 2%- per cent.,. nickel-4 percent,and carbon 0.3 per cent., by any open hearth process, by which a puresteel free from phosphorus and sulfur can. be obtained. If a mixture ofmolybdenum and. tungsten is used the equivalent quantity. of the mixtureshould be taken and for this purpose 1 per cent. of molybdenumisequivalent to about 2% per cent. of tungsten. For the purpose of themanufacture of armor platesthe ingots of this composition are rolled tothe desired thickness of plate,

and the plates covered with oak charcoal or other carbon on one surface,and heated for from seven to eightdays'at a red heat, as

is usual in the cementation process. Other articles can be formedandtheirsurfaces treated in a similar manner.

By the above treatment a plate having a glass hard surface is obtainedwithout quenching I also find that all or part of the nickel may bereplaced by cobalt.-

It will be seen that inthe above process the hardened plate orotherarticle is obtained without the necessity for heatingdifferent portionsthereof to different temperatures.

Having now described myinvention what I claim-as new and desire tosecure by Letters Patent is 1. Cemeiit steel plates or other articleshaving a glass-hard surface containing tungsten about 2-1- per cent.throughout the plate or article, carbon 0.2 to 0.5 per cent, through theback portion of the plate or article and a further proportion of carbonin the face of the plate or article, as set forth.

2. Cement steel plates or other articles having a glass-hard surfacecontaining about 2% per cent. of tungsten, 1 per cent.

of nickel and 0.3 per cent. of carbon.

throughout .the back portion of the plate or article and an additionalproportion of carbon in the face of the plate or article.

3. Cement steel plates or other articles having a glass-hard surfacecontaining both molybdenum and tungsten in quantity equivalent to about2% per cent. of tungsten, darbon 0.2 to 0.5 per cent. through the backportion of the plate'or article and a further proportionof carbon in theface of the'plate or article.

Cement steel plates or other articles having a glass-hard surfacecontaining both molybdenum and tungsten in quantity equivalent to about29 'per' cent. of tungsten, 4 per cent. of nickel and 0.3 per cent. ofcarbon throughout the back portion of the plate or article and anadditional proportion of carbon in the'face of the as set forth.- v Intestimony whereof I affix 'mysignature in presence of two Witnesses.

I j HAROLD ASHTON RICHARDSON. Witnesses:

ALFRED N. GARDNER, C. WALKER.

plate or article,

